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Topic: hooking up mach3 (Read 1966 times)

I have hooked up mach3 several tiems, but for some reason I am having difficulty this time. I have pins 2 & 6 hooked to -step and -direction (in that order), and a return wire running from +step and +direction to pin 24. Should I set the configuration for high or low? Am I missing something?

The problem was the laptop. I guess that time I submerged it in water and then stepped on it did some damage. I tried a different computer and everything works fine. Surprising cause everything else seems to work.

As you have things working now you'll probably not be interested but you have your driver wired in a slightly un-conventional way. As well as the active lo/hi thing, you can elect to use parallel ports outputs to either SOURCE or SINK current. "Normally" you would use them in sink mode. That is, you'd have a 5V supply to the +ve side of your step and dir driver inputs and then you'd use your parallel port pins to PULL the "-ve" side low (and thus SINK current). This is the way you'd more than likely HAVE to do things if you used optos.

You appear to be using your parallel port pins in current SOURCE mode. The issue here is that the amount of current parallel port pins can sink and source is USUALLY different. USUALLY they can SINK much more than they can SOURCE. This MAY be why your laptop appears to be otherwise OK - i.e. it PROBABLY IS but it just can't SOURCE enough current and hence the required ~5V is being pulled down too much to be a valid TTL high. If you tried SINK mode then it MAY work. BUT - As Hood says, laptops arn't recommended anyway (for this as well as other reasons).